Biodiesel fuels produced from vegetable oils have drawn much attention as alternate fuels for fossil fuels and also in terms of low emission of carbon dioxide, and therefore, an increase in demand for them has been expected. Since the production of such biodiesel fuels is accompanied by formation of glycerin as a by-product, it is required to make effective utilization of glycerin. As an effective utilization of glycerin, a process for producing acrolein from glycerin of a raw material is known. For example, Patent Literatures 1 to 5 disclose processes for producing acrolein by dehydrating glycerin and processes for producing acrylic acid by oxidizing acrolein obtained by dehydration reaction of glycerin.